"This system is vitally important to the defence of our homeland, and this test demonstrates that we have a capable, credible deterrent against a very real threat," he said on Tuesday.

It was the first live-fire test against a simulated ICBM for the Ground-Based Missile Defense (GMD).

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The interceptor, which was launched from Vandenberg Air Force, collided with a simulated missile launched from Kwajalein Atoll in the Marshall Islands over the Pacific Ocean, the agency said in a news release.